B. hominis mitochondria have no lactic dehydrogenase, isocitrate dehydrogenase, glycerol dehydrogenase, cytochrome oxidase, glutamate dehydrogenase, dihydrolipoemide, dehydrogenase, alpha keto-glutarate dehydrogenase, or pyruvate dehydrogenase enzymatic activity. B. hominis has an absolute requirement for cholesterol. The main acid products from glucose are acetic, propionic, succinic, lactic, and isovaleric acids. Spectrographic analysis for cytochromes and flavoprotein was negative. Thus, these mitochondria lack enzymes, as well as cytochromes that are normally present in mitochondria. Progress: Little was accomplished on this project in 1990-1991. In light of time required and time remaining for me, I suggest that it be ended. Study of cholesterol and fatty acid requirements are continuing under Z01CL1017602CP. Ultrastructure of B. hominis (major features) is on a solid footing now. There is much to done concerning the function of the central body and its role in schizogony. There are also questions to be answered re ameba-form ultrastructure, but these will wait for someone else's input.